Budke Raises Awareness About Neglected Diseases

Posted February 26, 2010

The earthquake in Haiti has pushed this most impoverished
country in the Western hemisphere into the spotlight and in doing
so, has drawn attention to the Cinderella diseases of the world:
neglected tropical diseases or NTDs.

Described as such by the World Health Organization (WHO) because
they persist "exclusively in the poorest and most marginalized
communities and have been largely eliminated elsewhere and thus are
often forgotten," NTDs affect more than 1 billion people worldwide.
They are highly prevalent in countries like Haiti that have high
levels of poverty and poor sanitation and medical systems.

Most NTDs kill slowly, causing life-long disabilities, which in
turn have severe consequences for both human health and livelihood.
Examples of these diseases are leprosy, lymphatic filariasis
(elephantiasis) and trachoma, characterized by debilitation,
thickening of the skin and underlying tissues, and blindness,
respectively.

The irony is that most NTDs are completely preventable. However,
the poor economic and political clout of their victims means that
there is little pressure on national or international health care
programs to prioritize funding for the control of these
diseases.

At the Texas A&M University College of Veterinary Medicine
& Biomedical Sciences, Dr. Christine Budke, assistant professor
of epidemiology, is aiming to change this.

Budke's research focuses on two NTDs-cystic echinococcosis (CE)
or hydatid disease and neurocysticercosis (NCC). Caused by
parasitic worms or helminths, CE and NCC affect both animals and
humans and are prevalent in poor rural agricultural communities
mainly in developing regions of the world, for example, areas of
China, the Middle East, Central and South America, and Africa.

By determining the global burden of these diseases-that is,
their total health, socioeconomic and financial cost to
society-Budke aims to highlight and improve their pariah
status.

A "two-fold hit"

"What makes [CE] exceptional...is that it is not only a
substantial human health problem but also has a considerable
economic effect on the livestock industries of some of the most
socioeconomically fragile countries," Budke and her coauthors
explained in a paper in 2006 titled the Global socioeconomic impact
of cystic echinococcosis.

NCC also causes this "two-fold hit," as Budke describes the blow
to not only human health but also livestock production inflicted by
these diseases. The involvement of both animal and human hosts in
the transmission cycles of CE and NCC explains this impact.

For example, the primary host of the tapeworm Echinococcus
granulosus, which causes CE, is the dog. Humans generally become
infected by accidentally ingesting tapeworm eggs in food or drink
contaminated with dog fecal material or during direct contact with
dogs. Livestock such as sheep, cattle and goats can also acquire
the infection from dog fecal material ingested during grazing.

In the case of NCC, humans are the primary host of the
disease-causing tapeworm Taenia solium and become infected by
accidentally ingesting tapeworm eggs in food or water contaminated
with human feces or by eating raw or undercooked infected pork.
Pigs also become infected by ingesting eggs shed in human
feces.

In both CE and NCC, the ingestion of tapeworm eggs results in
the formation of larval cysts, which form in various organ systems
and can have disastrous consequences for human and animal
health.

"Cysts [which in the case of CE form mainly in the liver and
lungs] can grow to be 12 centimeters [about 5 inches] across,"
Budke says. "These slow-growing cysts are space-occupying lesions.
They are almost like a cancer and they can kill you."

In NCC, cysts are formed in the brain and can cause seizures and
epilepsy. In fact, according to the WHO, NCC is the "most frequent
preventable cause of epilepsy in the developing world."

Also, in both CE and NCC, cyst infestation in livestock results
in economic losses due to livestock condemnation and production
losses.

Pariahs for various reasons

Despite these serious consequences to both human and animal
health, these diseases have not received due attention.

"The global burden of these diseases has never been determined
partly because there is no framework for reporting these diseases
at the regional, city or country level," Budke says, citing one
reason for the neglected status of CE and NCC.

In a paper published last year titled Zoonotic larval cestode
infections: Neglected, neglected tropical diseases? Budke and her
coauthors provided several reasons for the under-reporting of CE
and NCC.

One is that these diseases are often undiagnosed. This is
because tests for their early diagnosis, for example, abdominal
ultrasound, computer tomography and magnetic resonance imaging
scans, are not accessible to individuals in remote poverty-stricken
communities.

CE and NCC also remain undiagnosed because of their chronic
nature.

"Clinical signs associated with echinococcosis can take five to
ten years to develop, with clinical signs associated with NCC also
taking months or years to appear," Budke and her coauthors explain
in the paper. "For government administrations dealing with a myriad
of public health crises, this lack of acute symptoms may make these
conditions seem less dire than those with a shorter incubation
period."

Difficult treatment and complex control strategies have also
contributed to the neglected status of these diseases.

Treatment often involves the expensive surgical removal of cysts
and the administration of antihelminthic drugs for a minimum of six
months, which is not always effective. Control programs, which for
CE may include a combination of health education, vaccination of
secondary hosts such as sheep and the deworming of dogs, are not
easily implemented for various reasons.

"It is very difficult to sustain control measures," Budke says.
"A number of factors need to be considered." For CE, these include
controlling stray dog populations' access to offal (the organs of
butchered animals), the logistics of dog deworming and the cultural
or religious beliefs of societies, who believe in protecting and
adopting stray dogs, an important parasite reservoir.

The difficulty in addressing the abovementioned issues is
compounded by the limited funding available for controlling these
neglected diseases.

The way forward

"[These diseases] are really a one-health problem," Budke says,
stressing that both the human health and veterinary sectors must
take responsibility for managing CE and NCC. Shared control costs
and earlier detection of these zoonotic diseases are some
advantages of this partnership.

Budke also stresses the importance of determining the global
burden of CE and NCC, which involves estimating their health and
socioeconomic costs. In addition to providing information on
disease scope, global burden estimates will help raise awareness
about these diseases and in doing so, make funding control measures
for them a priority.

Budke and her collaborators hope that these approaches will
increase the profile of CE and NCC and prevent them from being
treated as "neglected stepchildren."